Extension-trestle



(No Model.)

J. HQ MAUST. EXTENSION TRES-TLB.

No. 583,384. Patented May 25,189'7 @X21/mmm rank Jasefgl T norms PErEns ca. PHcrrouTNo.. wAsHmGToN n c UNITED ,STATES PATENT EEicE.

JACOB H. MAUST, OF ALLEGHENY, PENNSYLVANIA.

EXTENSION-TRESTLE.

SPECMIGATION forming part of Letters Patent No. 583,384, dated May 25, 1897.

Application iiled February 24,1897. Serial No. 624,806. (No model.)

T0 all whom z' may concern.:

Be it known that I, JACOB II. MAUST, a citizen of the United States of America, residl ing at Allegheny, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Extension-Trestles, of which the followin gis a speciication, reference being had therein to the accompanyin g drawings.

This invention relates to certain new and useful improvements in extension trestles or scaffolds, and has for its object to provide a trestle that maybe easilyadj usted as required by the workmen and obviate the necessity of rebuilding the trestle or scaold, as required by the increased height of the building.

The invention aims to provide an extensible trestle which may be easily operated either from the ends or from the sides of the same, said operating mechanism being so arranged as to elevate the scaffold in such a manner as to keep the same perfectly level; and the invention further resides in the novel construction, combination, and arrangement of parts to be hereinafter more specifically described, and particularly pointed out in the claims.

In describing the invention in detail reference is had to the accompanying drawings, forming apart of this specilicatiomand wherein like figures of reference indicate similar parts throughout both the views, in which* Figure 1 is a perspective view of my improved eXtension-trestle. Fig. 2 isa detail view of a portion of the same, partly in section, to illustrate the operation of the rack.

Referring to the drawings by reference-iigures, l l indicate the uprights, which are grooved on their inner faces to receive the :rack-bars 2, connected together at their upper ends by a cross-piece 3. Engaging the uprights 1 is a cross-bar 4, provided with cutaway portions 5, in which is j ournaled the rollers 6 said cross-bar 4 being provided with bearings 7 7, in which is journaled the dogs 8 to engage the rack-bars 2. This cross-bar 4 is further supported by braces 9, which engage the supporting-legs 1l, and secured to the cross-bars 4 and 10 is a casing 12 and a brace 13, and journaled in said casing and brace is a shaft 14, carrying a roller 15 between the brace and casing, to which one end of the cords 16 is att-ached, said cords passbars 2.

ing over the pulleys G and having their other ends attached to the rack-bars 2.

In case it is desired to opera-te the trestle from the end instead of from the side I have provided a roller or shaft 17, which is journaled in the braces 9 9 and carries on its one end a crank 18. Attached to said roller are cords 20, which also pass over the pulleys 6 and are attached to the lower ends of the rack- The said operation is performed by means of a crank 1S on a shaft 17.

The operation of my improved extensible trestle will be readily apparent from the views of the same that I have shown in the drawings, as it will be noted that when the crank 2l is turned it will cause the cords 16, which are attached to the roller 15, to wind thereon, thus lifting on the lower end of the rack-bars 2 a'nd raising both these rack-bars simultaneously by reason of the cords 16 being attached to the roller l5 at opposite sides thereof, thus equally distributing the lift.

Practically the same operation is performed by means of the shaft 17, as when the crank 1S is turncd it causes the lines 20, which are attached to the said shaft, to wind thereon, thus lifting on the lower end of the rack-bars 2 and elevating the cross-piece 3, which forms the sill for the scaffold-platform. As this cross-piece 3 and the rack-bars 2 are being elevated the dogs S S will engage in the said rack-bars and hold the same at any position to which they may be adjusted, and when it is desired to lower the scaffold the removal of the dogs from engagement with the rackbars will permit the same to descend to the end of their downward path of travel. By this arrangement it will be noted that as the building increases in height the scaffold for the workmen may be easily adjusted to conform thereto without removing the entire trestle-work and platform and rearran gin gthe same, as is now The common practice.

It will be noted,fu rther,that various changes may be made in the details of construction without departing from the general spirit of my invention.

Having fully described my invention, what I claim as new, and desire to secu re by Letters Patent, is-

1. In an extension-trestle, the uprights provided with grooves on their inner faces, rack- ICO bars engaging in said grooves, a cross-piece connecting the upper end of said rack-bars, a cross-bar connected to the uprights, shafts j ournaled in said cross-bar and carrying rollers, a crank operating said rollers, dogs to engage the rack-bars, lines attached to the lower ends of the raclcbars, said lines passing over the rollers, and having their opposite ends attached to the roller carried by the shaft for elevating the rack-bars, a cross-piece supporting legs for the said trestle, substantially as shown and described.

2. In an eXtension-trestle, the combination of the uprights,provided with grooves on their inner faces, rack-bars engaging said grooves, a cross-piece connecting the upper end of said rack-bars, a cross-bar, dogs journaled in bearings on said cross-bar, su pporting-legs attached to said cross-bar, and means for ele vatin g the rack-bar and cross-piece to any desired height, substantially as shown and described.

3. In an eXtension-trestle, the combination .of the uprights, rack-bars operating therein,

a cross-piece connecting said rack-bars, a cross-bar connecting the uprights, rollers journaled in said cross-bar, dogs to engage the rack-bar, supporting-legs for said trestle, and a shaft having lines which are secured to the lower end of the rack-bars and pass over the pulleys to elevate the rack-bars and cross-piece, substantially as shown and described.

In testimony Whereof I affix my signature in presence of two Witnesses.

JACOB H. MAUST.

fitnessesz JOHN NOLAND, H. E. SEIBERT. 

